Chrysler Repair: Shuddering before downshifting, 1995 chrysler concorde, chrysler concorde

Question
Hi there. I have a 1995 Chrysler Concorde with a 3.5l engine with 110k miles. The problem is when I accelerate to 35 mph and take my food off the gas and coast, as the car decelerates from 35 to 30 mph, it begins to shudder and you feel it in the seat, then the steering wheel until it downshifts at 30 mph where it is smooth until it hits 25 mph when it starts shuddering again until 20 mph, when it downshifts and is smooth again. Acceleration is fine, and it does not slip while shifting. Chrysler rebuilt the transmission 2 years ago with a new torque converter, but the problem still was there. I just had the cv axels and the right tie rod replaced, tires rotated and balanced, a full tune up with plugs, wires, pcv, air and fuel filter, and the rear transmission mount replaced and the engine mounts inspected, but the problem is still there.  Nobody seems to have a clue on this. Any suggestions? Could the TCM need a flash with new software or have anything to do with it?  I'm at my wit's end. I cannot afford to buy a new vehicle with my job situation the way it is, and I can't continue to throw good money after bad.  Thanks for your time, Jason Kerner.

Answer
Hi Jason,
Becasue the problem wasn't corrected when the trans was rebuilt one would be tempted to believe that it is not related to internal mechanical issues (but that is a hope, not a fact because it assumes that the job was done right). Two ideas come to mind: have they tried reading out the transmission controller for fault codes, and have they measured the internal hydraulilc pressures at the various access ports to see what might specifically be out of spec? The second idea is based on a symptom chart for the trans:  for the "harsh downshift"* it gives as possible causes (starting with the simplest and going to the internal expensive to repair possibilities): engine idle speed too high, engine performance, aerated fluid, low fluid level, hydraulic pressures too high, valve body malfunction or leakage (valve body can be serviced without removing the trans), finally a bunch of internal possbibilities: warn or broken reaction shaft seal support rings, worn or damaged accumulator seal rings, damaged clutch seals, worn or faulty clutches (could be any except reverse or overdrive clutch). So check out the simple reasons, the code readout, and the internal pressure tests and then analyze the results to decide on which way to go from there, is my best suggestion.
*"poor shift quality" is another symptom which has the same possible reasons except for that: low hydrualic pressures and a dirty filter are possible causes, but none of the internal mechanical item are listed but one: worn or broken reaction shaft support seal rings.
There is no symptom such as 'shuddering on downshifts' offered unfortunately.
So I hope you can find a solution economically. The dealer's trans mechanic should be able to determine if the controller has the apropriate computer data installed or not when he does the fault code readout.
Roland